Social costs of fuel-vehicle pathways Fan Tong, Paulina Jaramillo, Ines Azevedo Department of Engineering and Public Policy (EPP) Carnegie Mellon University CEDM Annual Meeting 2017 May 24, 2017

Monetized damages due to air emissions On-road vehicles caused $56 billion air pollution damages for year 2005 (NRC, 2010). Transportation sector is the largest contributor to CO and NOX emissions. Traffic-related pollution accounts for about 20% of the deaths from PM2.5 in the United States (Lelieveld et al. 2015). On-road vehicles caused climate change damages with similar magnitude for year 2005 (NRC, 2010). Transportation sector is the largest contributor to CO2 emissions.

What are the climate change and air pollution (CC&AP) damages of different fuel-vehicle technology choices in the U.S.?

Life cycle emissions and marginal damages Air Pollution Damages (Species S, location L, height H) = Emissions (S, L, H) × Marginal damages (S, L, H) . Use the attributional life cycle assessment to attribute the air pollution damages throughout the life cycle to the functional unit. Climate Change Damages (pathway P) = Life cycle GHG emissions (pathway P) × Social cost of carbon (SCC).

Study scope Functional unit: vehicle mile travelled (VMT). Gasoline Diesel CNG LNG Grid electricity 2014 Primary energy extraction Crude oil production and transportation Natural gas production, processing, and transmission Fossil fuel production and transportation Fuel production and transport Oil refinery Natural gas compression Natural gas Liquefaction All power plants Petroleum product transportation [Assuming at refueling stations] Losses over transmission & distribution lines. Vehicle operation Conventional ICEVs and HEVs. SI-ICEVs SI-ICEVs; HPDI-ICEVs BEVs Vehicle type availability Functional unit: vehicle mile travelled (VMT). Reference year: 2014. Monetary unit: $2010.

“Best” pathways for local-haul trucks Climate change damages only Air pollution damages only Pathway that achieves the lowest CC&AP damages Both climate change and air pollution damages

How sensitive are the results to social cost of carbon (SCC)?

How sensitive is the spatial summary metric to SCC or VSL?

Trade-off between climate change mitigation and air pollution mitigation

Conclusions The fuel-vehicle combinations that provide largest reduction differ by vehicle types and by region. Trade-offs between climate change mitigation and air pollution mitigation. The estimates are sensitive to economic assumptions (SCC and VSL), emissions data (oil refining), and marginal damages of CAPs. How to reduce life cycle CC&AP damages? Fuel switching strategy may be effective in certain regions. BEVs in regions with cleaner electricity grids (Western U.S. and New England). CNG and LNG-HPDI trucks in regions with high population densities, such as West Coast and East Coast. Increasing fuel efficiency (hybrid electric vehicles) is effective in the remaining regions. Cleaning the electricity grid reduces damages not only from BEVs but also from other fuel-vehicle pathways.

Acknowledgements This study is supported by 2013-14 Northrop Grumman Fellowship. 2013-14 Steinbrenner Institute Graduate Research Fellowship. 2016 Ji-Dian Liang Fellowship. Conference travel support from CMU-GSA, CMU-EPP, and USAEE. Center for Climate and Energy Decision-Making (CMU & NSF; SES- 0949710). Center for Air, Climate and Energy Solutions (CMU & EPA; No. R835873). Fuels Institute. Fuel Freedom Foundation. Richard King Mellon Foundation. 11

Thank you! 12

Transportation sector is the largest contributor to CO2 emissions U.S. energy-related carbon dioxide emissions Unit: Million tonnes of CO2 (left); Billion tonnes of CO2 (right) https://www.eia.gov/todayinenergy/detail.php?id=29612 U.S. EIA (2017). Annual Energy Outlook 2017.

Transportation sector is also the largest contributor to CO and NOX emissions ORNL (2016). Transportation Energy Data Book. Edition 35. Table 12.1

Research questions What are the life cycle climate change and air pollution (CC&AP) damages of current transportation pathways for representative light-duty vehicles and heavy-duty vehicles in the U.S.? Which is the best fuel pathway for each vehicle type in each county? How sensitive are the results to value of a statistical life (VSL) and social cost of carbon (SCC)? Are there trade-offs between climate change mitigation and air pollution mitigation from fuel switching strategies?

Spatial details county, NERC region, Continental U.S.

Air pollution damages Emissions inventory/data Marginal damage models Heo et al. (2016)

Marginal damages of CAPs $ per an additional unit of mass emissions of a species S emitted at location L and height H. Model Data Year (Emissions, Population) Approach Spatial resolution Temporal resolution Pollutant Damage end point AP2 2011, 2011 Source-receptor matrix and damage functions. County centroid (3109 counties) Annual average PM2.5, SO2, NOx, NH3, VOC Health (short-term and long-term mortality and morbidity) and environmental impacts due to primary and secondary PM2.5 and ozone. EASIUR 2005, 2010 Reduced form models of chemical transport models, and damage functions. Grid cell size of 36 km×36 km (148×112 cells) Seasonal and annual average PM2.5, SO2, NOx, NH3 Health impacts (long-term mortality) due to primary and secondary PM2.5.

“Best pathways”